Former world number one Angelique Kerber suffered an early exit at the US Open but Ashleigh Barty is through to the second round.
Kerber, the 2016 champion in New York, was beaten on Monday 7-5 0-6 6-4 by France’s Kristina Mladenovic.
World number two Barty battled back from a set down to beat Kazakhstan’s Zarina Diyas 1-6 6-3 6-2.
Karolina Pliskova is also through after a topsy-turvy straight-set victory over Czech compatriot Tereza Martincova.
Pliskova, who lost to Kerber in the 2016 final, beat Martincova 7-6 (8-6) 7-6 (7-3) in a match that saw 12 breaks of serve, excluding both tie-breaks.
She will play Mariam Bolkvadze or Bernarda Pera in the second round while Barty will play Lauren Davis or Johanna Larsson.
“I was really pleased to be able to solve this riddle,” said Barty, who made 19 unforced errors in the first set against Diyas.
German Kerber’s poor form at Grand Slams this year continued with her opening defeat by Mladenovic, having been knocked out of the Australian Open in the fourth round, the French Open in the first round and Wimbledon in the second.